Seiko H024A Quick start guide

Movement
Item H024A
Jewels
Cal. No.
—
[SPECIFICATIONS]
•Hourly time signal
•Alarm test system
•Sound for button operation confirmation
•Battery life indicator
Additional mechanism
Monthly rate within normal temperature range: less than 15 secondsLoss/gain
Nil
Regulation system
Use 10-second gate.Measuring gate by quartz tester
SB-BU (SR1130W)
Battery life is approximately 3 years.
Voltage: 1.55V
Battery
(x 1.2)
Movement
size
Outside diameter ø31.0 mm
29.0 mm between 3 o’clock and 9 o’clock sides
28.5 mm between 12 o’clock and 6 o’clock sides
ø30.0mm
29.0 mm between 3 o’clock and 9 o’clock sides
28.5 mm between 12 o’clock and 6 o’clock sides
Casing diameter
5.5 mm
Height
Analogue section Digital sectionTime indication
Driving system Multiplex driving system
Step motor, 1 piece
2 hands
(Hour and minute hands)
Nematic Liquid Crystal, FEM (Field Effect
Mode)
•Time/calendar display
• Hour, minute and second
• Selection of 12h/24h-format indication
• Year, month, date, day of the week and
fully automatic calendar between the year
2006 and 2055
•Stopwatch display
•Hour, minutes, seconds and 1/1000
seconds
• Up to 23 hours 59 minutes 59 seconds and
999
• Data recall function
•Alarm display
• Daily alarm (2 channels)
•Timer
• Up to 23 hours and 59 minutes
•Time display
• Hour and minute hands, two
hands straight 10-second
increments
Display system
Cal. H024A
2 jewels
PARTS CATALOGUE /TECHNICAL GUIDE

PARTS CATALOGUE Cal. H024A
2/7
●For the part 6, please see the remarks on the following pages.
Disassembling procedures Figs. :
Reassembling procedures Figs. :
Lubricating : Types of oil Oil quantity
Moebius A
Moebius F
Silicone Oil 500,000 c.s.
Normal quantity
* Do not disassemble the
buttons except when
they need to be replaced.
Case back
Case back gasket
Movement
Hour, and
minute
hands
Dial
Button spring clip
Piezoelectric element
Button D
Button C
Button B
Button A
6
7
1
2
4
5Dial ring
Case ring
3
1
1
ed
ed
(AO-3)
(AO-2)

Cal. H024A
PARTS CATALOGUE
3/7
8
9
qa
qs
qd
qf
qg
q;
qh
qj
qk
w;
wa
wd
●For the parts , , , and , please see the remarks on the following pages.
ql wd e;8q;
Battery connection (–)
4270 380
Buzzer lead terminal
4246 368
Dial washer
0491 233
Insulator for circuit block
4216 366
Connector guard
4398 371
Connector guard screw
0012 316
Connector
4313 366
Liquid crystal panel
Liquid crystal panel frame
4540 366
0012 316
• Connector guard screw
(2 pcs.)
0012 168
• Switch spring screw
(2 pcs.)
• Train wheel bridge
screw(1 pc.)
• Coil block screw
(1 pc.)
Battery
(See the front page.)
Switch spring screw
0012 168
Train wheel bridge screw
0012 168
Train wheel bridge
0125 366
Intermediate center wheel
and pinion (B) 0817 155
Step rotor
4146 154
Coil block screw
0012 168
Coil block (B)
4002 366
Coil lead terminal
4246 367
Center wheel and pinion
Intermediate center wheel
and pinion (A)
0817 154
Hour wheel
Minute wheel and pinion
0261 380
ws
Main plate
Switch spring
Rotor stator (B)
4239 454
wf
wg
wh
wj
wk
wl
ea
es
ed
e;
ql
Circuit block
4004 139
0100 366

PARTS CATALOGUE Cal. H024A
4/7
Remarks
•Discrimination of the hand installation height
These parts are determined by the hand installation height. Refer to the table below to choose the
appropeiate part.
The caliber H024A has numerals to indicate the hand installation height, which is printed on the dial and
movement.
Standard typeStandard typeHeight
Numeral for
discrimination
Printed position
Printed on Dial Movement
Discrimination
22
Hour wheel
Center wheel
and pinion
Numeral for
discrimination
2
0221 607 0271 489
Part code
ql
ql
The numeral is printed at the
right end. The numeral is printed
below the caliber number.
• In a case where the numeral for discrimination is not printed on the movement (switch spring), see the
numeral printed on the dial or refer to the table above to identify each part by its shape.
Switch spring (standard type)
4250 010
Liquid crystal panel
The type of liquid crystal panel differs depending on the model. Refer to "SEIKO Watch Parts Catalogue (CD-
ROM)" or "Watch Parts Catalogue (SEIKO Watch Service Site)" to choose the appropriate type of the crystal
panel.
● Piezoelectric element 4589 006
Piezoelectric element, which is adhered to the case back, can be provided independently.
Center wheel and pinion Hour wheel
wd
e;
e;
q;

5/7
TECHNICAL GUIDE Cal. H024A
AC terminal
Tweezers Switch spring
I. STRUCTURE OF THE CIRCUIT BLOCK
2. To reset the circuit of the watch with its case back
closed, press the buttons “A”,”B”, “C” and “D” at the
same time and hold them for 2 to 3 seconds until the
display becomes blank. Then release the buttons and
check that the display shows “12:00’00” AM, Sunday,
January 1st” .
* Before closing the case back, apply a small quantity of
sillicon oil to the contact portion of the case back with
the buzzer lead terminal (piezoelectric element).
3. Be sure to set the digital time first before setting the
analogue time, as the analogue section is governed by
the "second" of the digital section.
* For time/calendar setting, refer to the instruction booklet
of each caliber.
1. After the battery is replaced with a new one, or after the
battery is re-installed following the repairing
procedures, be sure to short-circuit the AC terminal of
the circuit block and the switch spring with conductive
tweezers to reset the circuit as illustrated at right.
II. REMARKS ON INSTALLING THE BATTERY
H024A
H024A
A
BC
D
Upconverter coil
Crystal unit
AC terminal
Input terminal (–)
Buzzer output terminal
C-MOS-IC
Input terminal (+)
Coil output terminal
• The explanation here is only for the particular points of Cal. H024A.
• For the repairing, checking and measuring procedures, refer to the “TECHNICAL GUIDE, GENERAL
INSTRUCTIONS.”

6/7
TECHNICAL GUIDE Cal. H024A
III. REMARKS ON DISASSEMBLING AND REASSEMBLING
1. Set the switch spring in position, taking care not to
damage the two guide pins for the main plate. Then,
tighten the two switch spring screws.
• How to install
Battery
Switch spring
2. Make sure the two hooks of the switch spring engage
the main plate.
3. Insert the battery sideways, and have the hook of the
switch spring’s battery clamp portion catch the main
plate.
Use the universal movement holder for disassembling and reassembling.
Hour and minute hands
• Remarks on installing
After installing the battery in the movement, place the move-
ment on a flat metal plate or the like to install the hands.
* Install the hour and minute hands at the 12 o’clock position
within 60 seconds after resetting the circuit.
8
6
q;
• Remarks on removing the hands
When using a tool such as a bow-shaped hand remover,
exercise care so as not to damage the dial with the tool during
the hand removing process. Remove the hands either in the
direction of 2 o'clock and 8 o'clock or in the directions of 4
o'clock and 10 o'clock.
H024A
H024A
Guide pin
Hook
Hook
Battery clamp portion
Main plate
Switch spring screw

7/7
TECHNICAL GUIDE Cal. H024A
IV. VALUE CHECKING
1.3KΩ~ 1.5KΩ
•Time accuracy
To measure the accuracy, light up all the segments. To do so, press buttons “C” and “D” at the same
time in the TIME/CALENDAR SETTING display.
After the measurement, press any one of the button “A”, “B”, “C” or “D” to return to the TIME/
CALENDAR display.
•Coil block resistance
140Ω~ 200Ω
•Upconverter coil resistance
•Current consumption
For the whole movement : less than 3.76μA
For the circuit block alone : less than 1.3μA
Notes:
• Before measuring the current consumption, be sure to reset the circuit. Otherwise, current consumption
cannot be measured properly.
• When the current consumption for the whole movement exceeds the standard value, measure the
current consumption for the circuit block alone. If the result is within the standard value range of the
current consumption for the circuit block alone, overhaul and clean the movement parts and then
measure the current consumption for the whole movement again.
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